A brain-specific transcription activator, named BETA, that interacts with the kappa B (GGGGACTTTOC) transcriptional regulatory sequence - the binding site of the known factor NF-kappaB - was identified. BETA is expressed only in the gray matter of the brain and in primary cultures of neurons and astrocytes. This proposal will address questions regarding the structure and functions of BETA in order to elucidate its possible involvements in unique brain functions. BETA will be studied using 3 tools: (1) Protein extracts prepared from small regions of the CNS (e.g. hippocampus or parts of it) to be used in the electrophoretic mobility shift assay (EMSA) to assay for the DNA binding activity of BETA (2) Transfection of primary cultures of cerebellar and hippocampal neurons and of cerebellar astrocytes, with various promoter-reporter gene DNA constructs to study the resulting transcription activity. (3) When cloned, the BETA cDNA - to study BETA's structure and its transcription enhancing activity when introduced into heterologous cell-types; and, to study its levels of expression (by in situ hybridizations) in the CNS, under various circumstances. Using these tools the following experiments will be conducted: (1) The function of BETA in activating the proenkephalin promoter (which has 2 BETA binding sites, B1 and B2), in primary brain cultures, will be studied. (2) The function of NF-kappaB in activating proenkephalin transcription in activated T-cells, through the same (B1 and B2 sites, will be studied. (3) If (1) and (2) so indicate, a model that can explain the use of the same site by two distinct factors (BETA and NF- KAPPAb) in two different tissues (brain and lymphocytes, respectively) will be tested. (4) The possible involvement of BETA in HIV expression in brain cells will be addressed. (5) The structure of BETA in relation to NF- kappaB, will be studied. A reconstitution protocol for the 2 putative subunits of BETA with those of NF-kappaB will be developed. (6) An approach based on the reconstitution experiments, as well as other cloning procedures, will be used to clone cDNA(s) encoding BETA subunit(s). (7) The levels of expression of BETA at various developmental and functional states of the CNS in vivo and in primary brain cultures in vitro will be studied. (8) Finally, in the future, using the cloned BETA gene, the transcription factors which control BETA's own expression and the modes by which they are modulated at various CNS states, will be studied. It is hoped that the proposed experiments will contribute to understanding the role that the control of brain-specific gene expression plays in regulation higher brain functions.